Gold purity is measured in karat weight - which is the ratio of gold to other metals used to create a gold alloy.
Gold and the Properties of Gold
Gold is a dense, bright yellow colored element found in nature. Gold has the symbol AU (from the Latin: aurum) on the Periodic Table. Gold has many important properties. Gold is a good thermal and electrical conductor and is resistant to corrosion. It is a biocompatible metal - it's difficult to find anyone with sensitivity to pure gold. Gold is also is very soft and is commonly alloyed with other metals to increase its strength.
What is Karat Gold?
Karat gold is determined by the proportion of gold to alloy metal.
Gold is one of the softest and most malleable or pliable metals found on earth. Gold, in its purest form, is comprised of 100% gold with virtually no other metals added to it to strengthen it.
Karat gold is, by definition, the measure of its purity (or fineness) in proportion to alloy metal and is expressed in parts per thousand. Pure gold is 24 karat, which means it has a fineness of 1000. One karat is equal to 41.66 fineness.
Most Common Gold Karat Measurements
The various karat gold measurements are determined by the ratio of alloy metal to gold. The more gold an alloy contains, the higher the karat number. The most common karat gold densities are:
24 Karat Gold - This is gold in its purest form. It is 100% gold, with virtually no alloy metals added to it. Gold that is 24 karat is very soft and rarely used in jewelry.
22 Karat Gold - This karat gold contains 91.7% pure gold. It is alloyed with metals including sterling silver, copper and zinc, however, it is still fairly soft. Often, sterling silver is plated with 22 karat gold to give it a brilliant golden color.
18 Karat Gold - This alloy contains 75% pure gold and 25% alloy metals, like sterling silver or copper. This is a popular karat gold for jewelry, especially engagement and wedding jewelry, and features a lovely deep golden hue. It is considered to be the perfect balance of gold purity and strength.
14 Karat Gold - The most popular karat gold used in jewelry, 14 karat gold features 58.3% pure gold with the balance alloy metals. This karat gold features a lovely medium-golden hue and is a favorite for engagement and wedding jewelry, along with earrings, necklaces and bracelets.
10 Karat Gold - This karat gold contains 41.7 % pure gold. Since it contains more alloy metal, this is the lightest colored gold used in jewelry. This karat range is seen often in everyday jewelry and is usually very affordably priced.
What is a Gold Hallmark and What Does it Mean?
When you purchase an item made of karat gold, you will find a stamp, also called a gold hallmark, somewhere on the piece. It is stamped on the shank in rings and on the clasp for a necklace or bracelet. This hallmark indicates the gold karat strength used to create the design.
There are two different hallmarks that can be used to indicate gold karat or purity - the traditional hallmark and the modern hallmark. The traditional hallmark uses the gold purity percentage. Modern hallmarks are simply stamped with the karat weight, i.e., 14K.
|Karat Gold Hallmarks|
|Karat Measure||Traditional Hallmark||Modern Hallmark||Gold Purity|
Gold Karat vs. Carat - What's the Difference?
Sometimes you will see the terms karat and carat used interchangeably. While this is technically correct, the terms measure different things.
A karat is a measurement of the proportion of gold in an alloy of 24 parts. A carat is a unit of weight used to measure the size of a gemstone, like a diamond, ruby or sapphire.
For this reason, you will see gold described as 10K, 14K, 18K or 22K, and you will see diamonds and gemstones measures as 1 ct., 2 ct., etc.